Caustic flush method and apparatus for building water pipes



United States Patent [1113,536,08l

[72] Inventor August 11. Riess 2,222,516 11/1940 Powell et al. l34/22X4425 W. 169th St., Lawndale, California 2,425,848 8/ 1947 Vawter 134/1 11X 90260 2,603,227 7/1952 Paxton 134/22UX [21] Appl. No. 852,8122,653,420 9/1953 Ruth 134/22UX [22] Filed Aug. 25, 1969 2,835,234 5/1958Rasch et al. l34/22X [45] Patented Oct. 27,1970 3,010,853 11/1961Elliott 134/22X 3,156,584 11/1964 Yurdin 134/22X 3,169,545 2/1965Kolling l34/22UX 1 CAUSTIC FLUSH METHOD AND APPARATUS FOR 3,295,5381/1967 Williams... 134/111 BUILDING WA'IZER PIPES 3,431,145 3/1969 Riley134/22 9 Claims 1 Drawmg Fig. Primary Examiner-Joseph Scovronek [52]U.S. Cl 134/22, Assistant Millman 134/103, 34/111, 134/169Attorney-Howard L. Johnson [51] Int. Cl B08b 9/06; C23g 3/04 [50] FieldofSearch 134/22, ABSTRACT; A portable assembly cgntaining hydraulicpres- [56] References Cited UNITED STATES PATENTS 1,049,054 12/1912Coombs 134/22UX 1,892,093 12/ 1932 Battistella 1. 134/22X 2,009,9557/1935 Burns 134/169UX 2,089,317 8/1937 Wilder l34/22X sure gages, pump,heater, filter and mixing tank for caustic soda or otherdeposit-dissolving chemical(s), which tank can be coupled to two pointsof a building water system forming a closed loop for liquid circulationwhich may include each of the hot and cold water systems separately, butomit the hot water tank of the building. Removal of calcium incrustationwithin the pipe course and restoration of initial flow capacity can bejudged by comparison of hydraulic pressure at beginning and end of thetreated length.

CAUSTIC FLUSH METHOD AND APPARATUS FOR BUILDING WATER'PIPES STATEMENT OFTHE INVENTION Particularly in localities where the local geologicalstructure of the water source results in hard water", that is, having arelatively high mineral content (particularly calcium), the continueduse of such water supply when piped into household and other edifices,resultsin a progressive deposition of calcium within the smaller pipesor conduits, especially in that portion carrying hot water (from thebuilding water heater). Thus with Vz-Ol' ii-inch pipes which arecommonly used in smaller buildings, over a period of years the mineraldeposition may reduce the maximum flow at a faucet to a mere trickle.There has been no practical or satisfactory way to restore such flowshort of replacing the pipes and fixtures. When such pipes are enclosedin the walls, as is usually the case with vertical conduits, the wallshave to be broken open to gain access; and the total cost of' restoringboth the pipes and the wall is expensive. By the present method andapparatus, however, such deposits can be removed from within thebuilding water conduits without removing the conduits, or fracturing thebuilding walls to get to them.

At an accessible location such as the connection of an interior plumbingfixture (e.g. wash basin, tub, shower, commode, etc.) to the buildingwater conduits, the normal con nection is transiently interrupted andrecoupled to the present assembly, and a similar connection is made tothe assembly from a more remote point in the system, so as to form aclosed path through the present operating assembly. The latter thenprovides a mixing chamber, pump, filter, and hydraulic gage means sothat cleaning liquid can be recirculated through this closed path orloop for the required period of time. As noted in the above abstract,this time may be monitored by comparison of the difference in pressurethrough the treated portion of the conduits, as well as by noting theabsence of loosened particles of rust or calcium in the flow as itreturns to the tank (and before it passes through the filter unit(s)).

When the pressure or flow rate has thus been restored to normal, theclosed path is opened by connecting the distant point to an outlet, thecaustic is purged, and the system flushed with fresh water and recoupledto its initial connections. Such an operating unit is portable and canbe readily moved from one job or location to another. Likewise, such arejuvenating procedure can now be readily carried out relativelyfrequently, such as every year or two, so as to permanently maintain afull flow of water rather than awaiting the occurrence of a grossimpedance in the line before attempting remedial action. The presentsystem and apparatus can likewise be used to rejuvenate steam boilersand other industrial systems which recycle liquids and consequentlybecome internally obstructed by corrosion and depositions from the I 55The most practical and readily available water-soluble water or otherfluid.

cleaning agent for this purpose is caustic soda (sodium hydroxide)although other substances may be employed (alone or in combination). Thecaustic soda may be transported in the dry or solid state and added towater in themixing tank at the time of use; of course carboys of aqueous(concentrated) sodium hydroxide can similarly be used.

The period of caustic treatment will vary with theliquid flow rate, pumppressure, thickness and non-uniformity of depositions or obstructions,treating temperature (both of liquid and of pipes), concentration oreffective strength of the cleaning composition, etc. Conveniently, about1 pound of sodium hydroxide flakes are added for 8 gallons of water inthe mixing tank 30, and this concentration may be circulated through aclosed loop or path of the conduit system for a period of about 1 to 3or 4 or more hours. Subsequent flush or clean out of the system withfresh water may be accomplished '7 portable assembly, partly in verticalsection and partly in elevation, operatively connected to the conduitsof a building water system which are represented schematically.

The portable assembly 10 here depicted provides a pair of rear wheels 12and a forward, caster-type wheel 14 connected to a carriage body 16 bysuspension brackets 18, 20, with an upward projecting, handle bar 22extending across the rear for guiding the assembly when manually movingit to and from a work location. A dependent housing supports an electricmotor 24 which operates a pump 25 by way of drive shaft 26. Electriccurrent is obtained from a building outlet by an electric line 27, whichalso supplies a series of resistance units 28 which are supported atopan asbestos plate 29 and underlie the bottom wall of a liquid tank 30for which they form a heating unit.

The body 16 of the assembly is formed with an outer wall 17 and an innerwall 19, separated by a thickness of insulating material 21 so as toform a heat-retaining liquid container or tank 30. Across the tankbottomis lodged a removable filter screen 32 which overlies a centraldrain outlet 33 for the tank. The open top of the tank is closed by agenerally rectangular cover 34 which is removably secured by aperipheral series of edge-located fastening elements 35. The top edge ofthe inner wall 36 of the cover is slanted convergingly downward to forma horizontally disposed, filter screen 37 which spacedly underlies anannular, courser, baffle plate 38 which in turn is centered beneath theoutlet mouth 39 of a conduit 40 which overlies the cover and issupported thereabove by a bracket 41. The conduit 40 is further securedat its outlet end by an annular fitting 42 which centers it respectivelyover the baffle plate 38, screen 37 and the body of the tank 30.Intermediate its supported length, the conduit is provided with aninspection window 43 and a shut-off valve 44. More distally, there is apressure gage 45 and a dependent length 46 with its shut-off valve 47and an outlet 48 to a sewer or drainage line 49 (which may be aninstallation at the location where the apparatus is used).

Within the liquid area of the tank is a float 50, pivoted to the innerwall at 51 and with a lever arm 52 extending upward within a guide hoop53 so as terminally to dispose a liquidlevel indicator 54 adjacent aread-out window 55 of the cover 34.

Beneath the floor of the tank 30 is a composite control valve andconduit chamber 57 (here represented schematically on a vertical planefor greater clarity). Conduit 58 from caustic tank outlet 33 goes past ashut-off valve 59 and temperature sensor 60, and through a connectingconduit 61 into the delivery pump 25 from which the liquid flow emergesthrough conduit 62, where at coupling 63 it can be joined to a buildingwater supply system as by flexible conduit 70. The conduit 62 is alsoconnected to a linking conduit 64 which through a shutoff valve 65 isjoined to the pump inlet line 61, and through a T 66, check valve 72 andflexible conduit segment 67 can be coupled to the outlet valve 68 of thehot water supply tank 69 of the building plumbing system. Thus, with thevalve 59 closed and the hot water valve 65 open, the pump 25 may be usedto circulate the heated water of tank 69 through the cold water lines ofthe building to which the pump delivery conduit 62 is at that timeconnected through coupling 63 and flexible conduit 70. Or, without theoperation of pump 25, the hot water from building tank 69 may simplyflow through the lines 67, 66, 64, and out 62 into the connected coldwater lines-as long as the inlet line 71 of the tank is supplied by themunicipal water pressure.

The building pipes thus connected may be heated by circulation of hotwater from the tank 69 prior to flushing with cleaning solution fromcaustic tank 30, and the heated water may then be allowed to flow to acustomary drain simply by opening valve 47 and closing valve 44. Apre-treatment can of course also be applied to the hot water pipes of abuilding simply by running the hot water of tank 69 through them beforecirculating the caustic of tank 30. Such conduit heating beforecontacting them with cleaning solution, makes the action of the cleanermore effective; that is, it acts faster to loosen or dissolveencrustations when the temperature is higher.

Attachment of the present assembly to a building water system canconveniently be made at the first installation of a plumbing fixture inthe building, beyond the water meter, such as a wash basin 11 which mayhave either of its hot or cold supply lines disconnected from thebuilding conduit at the adjacent union 23, and the flexible conduit 70coupled thereto. A building conduit 73 of the same (hot or cold) systemwhich (preferably) is returning from a distant part of the building, iscoupled to the conduit 40 at 74, as by another length of flexible hose.With the valve 47 closed and the valve 44 open, the cleaning solutionfrom tank 30 is circulated through the system by pump 25 (afterpreliminary pipe-heating, as just described) until the initial hydraulicpressure as shown by the gage 56 is decreased by no more than, say, 10percent at gage 45, and the inspection window 43 no longer shows passingsediment particles. The valves 44 and 59 are then closed and the valves47 and 68 are opened to allow fresh water (from line 71) to flush outthe system and be vented through drain 49. This flush volume need not beheated in passage through tank 69 (that is, the heating unit may beturned off). If pump operation is desired for this flush operation, thevalve 65 is also open and valve 75 is closed.

If the valve 65 is closed and the pump 25 stopped, the city water fromthe line 71 will register its pressure at gage 56. With the valves 44and 47 closed, the final pressure is indicated at gage 45. Thedifferential of the two pressures will show the drop in pressure due torestrictions in the line. Such difference determined before and aftercaustic treatment, will show the improved pressure gained by thetreatment.

In summary, it is not desirable to run the caustic solution through thetubes of the building hot water heater, which are usually made ofcopper. Accordingly, if the first connection of the present assembly ismade at the building shut-off valve (adjacent the entrance water meter),the distant connection is then made just prior to the hot water heaterand this length of conduit is cleaned by itself. The two connections canthen be detached and recoupled to the hot water lines (a) at the unionjust beyond the hot water heater, and (b) at the remote end of the hotwater lines, and this length (which carries the greatest amount ofdeposition) is then caustic treated. However, the cold water lines canbe treated as a single unit, and even simultaneous with the treatment ofthe hot water line, if two assemblies 10 are used; in this case, thecold water lines would be cleaned in shorter time than the hot waterlines (beyond the heater 69) due to less deposition.

lclaim:

l. The method for removing pressure-reducing liquiddepositedencrustations from the interior of a course of normallyliquid-conducting conduits, which method comprises:

disconnecting a portion of said course of conduits at two locations andtemporarily coupling together said two locations to form a closed pathfor repetitive circulation of liquid through the disconnected portion;circulating a liquid containing an encrustation-loosening componentthrough said closed path and removing loosened encrustations from thecirculating liquid;

measuring the liquid pressure at two locations along said disconnectedportion which show a drop in pressure resulting from the presence ofsaid encrustations, and continuing the circulation between saidlocations until the downstream pressure at the second location has beenrestored approximately to its initial pressure by removal of thecausative encrustations; and

flushing out said encrustation-loosening component from the closed path,uncoupling the temporary connection of the two locations, andreconnecting the conduits for their normal conveyance of liquid.

2. The method of claim 1 wherein said liquid containing anencrustation-loosening component is circulated at an elevatedtemperature resulting from the deliberate application of heat. 3. Themethod of claim 1 wherein said encrustation-loosening componentcomprises sodium hydroxide.

4. The method of claim 1 which is applied to water conduits which arepermanently installed within the walls of a building.

5. The method of claim 1 which includes circulating through said closedpath which is formed through the cold water conduits of a building,heated water directed therethrough from the hot water system of saidbuilding prior to circulation of said encrustation-loosening component.

6. A portable assembly of the character described, comprising incombination:

container means for introducing liquid-dispersibleencrustation-loosening material into a fluid flow directed therethrough;means for coupling said container means to a selected portion of aconduit system which forms a liquid distribution system such as thewater distribution system of a building, so as to form a continuous pathfor liquid circulation jointly through said portion of conduits and thecoupled container means; pump means adapted to circulate the liquiddispersed encrustation-loosening material through said continuous path.and filter means for removing from said path, solid particles loosenedfrom said conduits by the pumped fluid flow; and fluid-pressuremeasuring means located at two locations along said continuous path,whereby the progressive removal of internal conduit encrustation by thepumped fluid can be gaged by comparison of the difference of pressure.7. The portable assembly of claim 6 which additionally includes heatingmeans for heating the circulating fluid.

8. The portable assembly of claim 6 which includes flexible conduit andcoupling means adapted to connect said selected portion of a conduitsystem with said container means and pump means at two points to form aclosed path through the assembly.

9. The portable assembly of claim 6 which includes conduit and couplingmeans adapted to selectively join to said continuous path a hot waterproducing unit of the water system of the building.

